Whether over the Internet or your office network, wherever there is data flow, performance matters. Network bandwidth is one of the most important factors that determines performance.

The demand for it is increasing with time. With advanced technologies in use, newer applications need more bandwidth to perform smoothly. As an engineer, you have to know network bandwidth inside and out to set up high-performance networks and build faster applications. If that’s what you’re looking for, you’ve come to the right place.

In this blog post, I will start by explaining what network bandwidth is and why it important. Then I’ll tell you how to measure and improve it.

Network bandwidth gauge smoking

What Is Network Bandwidth?

Network bandwidth is the maximum amount of data that can be transferred through a communication channel at a given time. It is usually measured on a per-second basis. Let’s say you have two computers connected with a LAN cable. The maximum number of bits of data that can be transferred through this cable in a second is its bandwidth. For example, if you are using a Cat 6 cable, it can transfer a maximum of 1 GB per second.

Network bandwidth is often confused with network speed. People tend to use the two terms interchangeably, which is technically wrong. Let’s take the example of a highway. The maximum number of vehicles the highway can accommodate is the bandwidth. And how fast these vehicles can drive on this highway is its speed.

Let’s say you want to download a file from the internet, and the file size is 3 MB. Suppose your Internet bandwidth is 1 Mbps and your internet speed is 10 Mbps. In this case, it would take 3 seconds to download the file because your bandwidth allows you to transfer only 1 MB of data per second. But if your bandwidth was 5 Mbps, it would take less than a second to download the file.

In a real-life scenario, it is important that both network bandwidth and network speed are high. It would make no sense to have a very high network bandwidth with a slower speed or vice versa.

Raw Bandwidth vs. Effective Bandwidth

Depending on where you are measuring the bandwidth, it can be categorized into two types: raw bandwidth and effective bandwidth.

Raw bandwidth is the total maximum amount of data transfer that can happen on a network. In some cases, you might have various devices on the network. If these devices have different bandwidths, that becomes the effective bandwidth the device can use.

For example, let’s say I set up a network with 1 Gbps bandwidth. And suppose I have a modem on this network. The network data has to go through the modem, which could reduce the bandwidth due to the latency.

Effective Bandwidth = Size of Data / Total Latency

Latency consists of all the delays in the network. Some common latency factors include the sender and receiver overhead, time of flight, and transmission time. Sender and receiver overhead is the time it takes for the message to move from the sender’s buffer onto the network and from the network to the receiver’s buffer. Time of flight is the amount of time data spends on the network channel. Transmission time is the point in time when the transmission begins to the point in time when it ends.

When someone says “network bandwidth,” they usually mean absolute bandwidth unless they specifically say otherwise.

Now let’s see why it matters.

Why Is Network Bandwidth Important?

It’s obvious that you need high-performance applications to impress your customers. And that’s exactly why network bandwidth matters. It plays a very important role when there are applications that communicate with each other or with other applications. I’ll show you a few examples and explain how bandwidth matters for performance.

Cloud-Based Servers

Cloud-based servers are used more commonly now. If you use the cloud just to store data, it won’t make a lot of difference. But if you use a cloud server to host your application, network bandwidth matters. When you host a server, the server will receive requests from the clients. Based on the demand, your server can have hundreds or millions of requests per day. These requests are nothing but data. And the way they reach your server is through the network. The number of requests the server can receive and respond to is determined by the network bandwidth.

Let’s say that each request takes up to 5 MB of data on average and the response takes up to 20 MB. If your network bandwidth is 100 Mbps, your server can only accept and respond to four requests per second.

Having a greater bandwidth will help the server attend to more requests, and your business will get more customer engagement during the same amount of time.

Distributed Applications

Distributed applications are programs of software than run on different systems but communicate and collaborate with each other to get the work done. The communication between these applications and systems happens through a network. And because communication is nothing but data flow, network bandwidth determines the efficiency and performance of distributed applications.

One good example of how network bandwidth affects distributed applications is online multiplayer gaming. When various players connect together through a network to play games, the data being transferred is more than on an average website. It is important that this huge amount of data has no lag so the players can stay in sync in the game.

So in general, wherever there is data flow, network bandwidth plays an important role in deciding how well the applications and systems perform. It is better to know if you have enough bandwidth before running the application than after you run it. You can figure that out by measuring the network bandwidth.

How to Measure Network Bandwidth?

The straightforward method for measuring network bandwidth is by placing two hosts at each end of the network, then initiating data transfer from one to the other. You can send packets using TCP utilities and then check the maximum amount of data transfer in a given time. Another approach is to transfer files of known size and measure how much time it took for the file to reach to the destination. You can then divide the size by the total time to get the average transfer size in a second. To get accurate results, make sure your network speed is maxed out. Measuring network bandwidth during the initial phases after the setup will help you determine the bandwidth. But over time, when there will be a number of hosts on the network, it is also important to monitor the bandwidth in addition to measuring it.

Monitoring Network Bandwidth

Bandwidth monitoring tools help you measure and monitor bandwidth in real time. This helps you identify problems in the network and decide if you need to increase the bandwidth. A bandwidth monitoring tool like Scalyr will display the network’s upload and download speeds along with the time so you can understand what might be the reason for whatever behavior you’re seeing.

This tool make it easy for you to understand what’s happening with your network. So whether you’re setting up or optimizing networks or building applications that greatly depend on the network for performance, I suggest preparing yourself with this tool. Along with network monitoring, Scalyr provides log monitoring for operating systems as well as applications, so it’s a one-stop solution, and you can try it for free.

This post was written by Omkar Hiremath. Omkar uses his BE in computer science to share theoretical and demo-based learning on various areas of technology, like ethical hacking, Python, blockchain, and Hadoop.

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